JEE Main & Advanced Physics Motion in a Straight Line / सरल रेखा में गति Question Bank

done Relative Motion Total Questions - 13

• question_answer1)
  Two trains, each 50 m long are travelling in opposite direction with velocity 10 m/s and 15 m/s. The time of crossing is                                                                                                              [CPMT 1999; JIPMER 2000; RPET 2001]
  A)
           \[2s\]                              done clear
  B)
           \[4\,s\] done clear
  C)
           \[2\sqrt{3}s\]                  done clear
  D)
           \[t=\frac{{{\nu }_{1}}-{{\nu }_{2}}}{a}\] done clear
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• question_answer2)
  A 120 m long train is moving in a direction with speed 20 m/s. A train B moving with 30 m/s in the opposite direction and 130 m long crosses the first train in a time [CPMT 1996; Kerala PET 2002]
  A)
           \[6\,s\]                            done clear
  B)
           36 s done clear
  C)
           38 s                                done clear
  D)
           None of these done clear
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• question_answer3)
  A 210 meter long train is moving due North at a of 25m/s. A small bird is flying due South a little above the train with speed 5m/s. The time taken by the bird to cross the train is                 [AMU (Med.) 2001]
  A)
           \[6s\]                              done clear
  B)
           \[7s\] done clear
  C)
           \[9s\]                              done clear
  D)
           \[10s\] done clear
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• question_answer4)
  A police jeep is chasing with, velocity of 45 km/h a thief in another jeep moving with velocity 153 km/h. Police fires a bullet with muzzle velocity of 180 m/s. The velocity it will strike the car of the thief is           [BHU 2003; CPMT 2004]
  A)
           150 m/s                          done clear
  B)
           27 m/s done clear
  C)
           450 m/s                          done clear
  D)
           250 m/s done clear
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• question_answer5)
  A boat is sent across a river with a velocity of 8 km/hr. If the resultant velocity of boat is 10 km/hr, then velocity of the river is:                                                [Pb. PET 2004]
  A)
                 10 km/hr                           done clear
  B)
                 8 km/hr          done clear
  C)
                 6 km/hr                    done clear
  D)
                            4 km/hr done clear
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• question_answer6)
  A train of 150 meter length is going towards north direction at a speed of \[10m/\sec \]. A parrot flies at the speed of \[5\,\,m/\sec \] towards south direction parallel to the railway track. The time taken by the parrot to cross the train is [CBSE PMT 1992; BHU 1998]
  A)
           12 sec                            done clear
  B)
           8 sec done clear
  C)
           15 sec done clear
  D)
           10 sec done clear
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• question_answer7)
  A boat is moving with velocity of \[3\hat{i}+4\hat{j}\] in river and water is moving with a velocity of \[-3\hat{i}-4\hat{j}\] with respect to ground. Relative velocity of boat with respect to water is:                                                                  [Pb. PET 2002]         
  A)
                                        \[-6\hat{i}-8\hat{j}\]              done clear
  B)
                 \[6\hat{i}+8\hat{j}\]          done clear
  C)
                 \[8\hat{i}\]                        done clear
  D)
                            \[6\hat{i}\] done clear
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• question_answer8)
  The distance between two particles is decreasing at the rate of 6 m/sec. If these particles travel with same speeds and in the same direction, then the separation increase at the rate of 4 m/sec. The particles have speeds as                [RPET 1999]
  A)
           5 m/sec ; 1 m/sec           done clear
  B)
                               4 m/sec ; 1 m/sec done clear
  C)
           4 m/sec ; 2 m/sec           done clear
  D)
           5 m/sec ; 2 m/sec done clear
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• question_answer9)
  A boat moves with a speed of 5 km/h relative to water in a river flowing with a speed of 3 km/h and having a width of 1 km. The minimum time taken around a round trip is               [J&K CET 2005]         
  A)
                5 min                                 done clear
  B)
                           60 min          done clear
  C)
               20 min                              done clear
  D)
                            30 min          done clear
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• question_answer10)
  For a body moving with relativistic speed, if the velocity is doubled, then                                [Orissa JEE 2005]
  A)
                Its linear momentum is doubled                               done clear
  B)
                           Its linear momentum will be less than double          done clear
  C)
                 Its linear momentum will be more than double                   done clear
  D)
                 Its linear momentum remains unchanged done clear
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• question_answer11)
  A river is flowing from W to E with a speed of 5 m/min. A man can swim in still water with a velocity 10 m/min. In which direction should the man swim so as to take the shortest possible path to go to the south.    [BHU 2005]
  A)
                30° with downstream              done clear
  B)
                           60° with downstream          done clear
  C)
                           120° with downstream            done clear
  D)
                           South done clear
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• question_answer12)
  A train is moving towards east and a car is along north, both with same speed. The observed direction of car to the passenger in the train is                  [J & K CET 2004]         
  A)
                 East-north direction           done clear
  B)
                            West-north direction          done clear
  C)
                 South-east direction          done clear
  D)
                 None of these done clear
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• question_answer13)
  An express train is moving with a velocity v1. Its driver finds another train is moving on the same track in the same direction with velocity v2. To escape collision, driver applies a retardation a on the train. the minimum time of escaping collision will be              [RPET 2002]
  A)
                 \[t=\frac{{{v}_{1}}-{{v}_{2}}}{a}\]                  done clear
  B)
                            \[{{t}_{1}}=\frac{v_{1}^{2}-v_{2}^{2}}{2}\]          done clear
  C)
                 None                                 done clear
  D)
                 Both done clear
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